Galaxies and Galactic Terminology

Question 1

What are the Clouds of Magellan?

Answer 1

Two irregularly shaped galaxies, on large and the other small, relatively near to our Milky Way galaxy. Visible by eye from the southern hemisphere, usually denoted as LMC and SMC.

Question 2

What is a cluster?

Answer 2

A group of apparently near by objects; clusters of stars or galaxies. Star clusters are open or globular.

Question 3

What is the Crab Nebula?

Answer 3

Remnant of the supernova observed in 1054 AD, now observable as an expanding and tangled cloud of gas, with a pulsar at the center.

Question 4

What is an elliptical galaxy?

Answer 4

Type of galaxy that appears to have an elliptical shape and contains no visible interstellar material.

Question 5

What does extragalactic mean?

Answer 5

Beyond the Milky Way galaxy.

Question 6

What is a galactic cluster?

Answer 6

Cluster of stars with an open (not too closely packed) appearance, as opposed to globular cluster.

Question 7

What is the galactic equator?

Answer 7

Central plane of the Milky Way galaxy.

Question 8

What is galactic longitude and latitude?

Answer 8

System of coordinates useful in specifying the location of objects with respect to the galactic equator (for latitude) and the direction toward the galactic center (for longitude).

Question 9

What is a galaxy?

Answer 9

Large number of stars with their interstellar gas and dust, grouped into a region that is well separated from other galaxies.

Question 10

What is the halo of a galaxy?

Answer 10

Region of a spiral galaxy that extends away from the flattened disk, and contains few stars, some globular clusters, making a roughly spherical overall shape for the galaxy.

Question 11

What is an irregular galaxy?

Answer 11

Galaxy that has no symmetrical or spiral shape.

Question 12

What is a local group?

Answer 12

A group of galaxies bound by the forces of gravity.

Question 13

What does the Milky Way refer to?

Answer 13

Bright band that stretches across the sky, produced by large number of stars and other bright objects that lie near the equatorial plane of our galaxy.

Question 14

What is the Milky way galaxy?

Answer 14

Concentration of stars, gaseous nebulas, interstellar gas and dust in which the Sun and solar system are located.

Question 15

What is a nebula?

Answer 15

Object with nonstellar appearance. Objects originally labeled as nebulae are now known to include galaxies (Andromeda is one), clouds of gas and dust (Orion nebula), and supernova remnants (Crab nebula)

Question 16

What is an open cluster?

Answer 16

Galactic cluster of stars in which the individual stars can be seen, located within the spiral arm of disk of the galaxy

Question 17

What is a pulsar and where does it originate?

Answer 17

Object that emits pulses of radiation with extreme regularity. Pulse periods for different objects range between 1.5 thousandths of a sec and about 5 sec. Pulsars are thought to be rotating neutron stars, extremely compact objects of great density

Question 18

What is a quasar? What are its qualities?

Answer 18

Object that appears starlike but its actually extra-galactic, moving away from us at high speed. Distance, deduced from velocity-distance relation, is very large and extremely luminous.

Question 19

What is a spiral galaxy?

Answer 19

Type of galaxy that has a flattened shape, with arms of stars and gas and dust extending either from the nucleus or from short bars that are themselves connected to the nucleus.

Question 20

Name the five main types of galaxies.

Answer 20

Spiral, Elliptical, Dwarf, Interacting, Starburst